Polls closed in Georgia on Tuesday after voters cast ballots in a pair of runoff elections that will determine both control of the US Senate and Democratic President-elect Joe Biden's ability to push through an ambitious legislative agenda.
Republican incumbents David Perdue and Kelly Loeffler faced Democratic challengers Jon Ossoff, a documentary filmmaker, and the Rev Raphael Warnock, a pastor at a historic Black church in Atlanta.
The results could be known by Wednesday, Georgia Secretary of State Brad Raffensperger told CNN, although the outcome may remain in doubt for days if the margins are razor-thin. Officials were set to begin counting ballots as soon as polls closed at 7 p.m. (0000 GMT), although a handful of sites will stay open later after earlier delays.
Democrats must win both contests in Georgia to take control of the Senate. A double win for the Democrats would create a 50-50 split in the Senate, giving Vice President-elect Kamala Harris the tie-breaking vote after she and Biden take office on Jan. 20. The party already has a majority in the House of Representatives.
If Republicans hold onto the Senate, they would effectively wield veto power over Biden's political and judicial appointees as well as many of his policy initiatives in areas such as economic relief, climate change, healthcare and criminal justice.
Both Biden and Republican President Donald Trump campaigned in the state on Monday, underscoring the stakes.
No Democrat has won a U.S. Senate race in Georgia in 20 years, but opinion surveys show both races as exceedingly close. The head-to-head runoff elections, a quirk of state law, became necessary when no candidate in either race exceeded 50% of the vote in November.
Biden's narrow statewide win in the Nov. 3 election - the first for a Democratic presidential candidate since 1992 - has given the party reason for optimism in a state dominated by Republicans for decades.
More than 3 million Georgians voted early by mail or in person, shattering the record for runoff elections even before Election Day arrived. The two races drew nearly half a billion dollars in advertising spending since Nov. 3, a staggering total that fueled a tsunami of television commercials.
An exit poll of more than 5,200 voters released by Edison Research on Wednesday showed the electorate's racial mix appeared to be roughly the same as in November. About six in 10 voters identified as white, while roughly three in 10 were Black and the remainder split among Latino, Asian and other groups.
The poll included both early voters and voters who cast ballots on Tuesday.
In Smyrna, about 16 miles (26 km) northwest of Atlanta, Terry Deuel said he voted Republican to ensure a check on Democratic power.
"The Democrats are going to raise taxes," the 58-year-old handyman said. "And Biden wants to give everyone free money - $2,000 each or something like that for COVID stimulus? Where are we going to get the money?"
Ann Henderson, 46, cast ballots at the same location for Ossoff and Warnock, saying she wanted to break Washington's gridlock by delivering the Senate to Democrats.
"It's the social issues - civil rights, racial equality, voting rights, pandemic response," she said. "If we take it, maybe we can get something done for a change."
The campaign's final days were overshadowed by Trump's continued efforts to subvert the presidential election results.
On Saturday, Trump pressured Raffensperger, a fellow Republican, on a phone call to "find" enough votes to reverse Biden's victory, falsely claiming massive fraud.
Trump's efforts to undo his loss - with some Republicans planning to object to the certification of Biden's win when Congress meets on Wednesday to formally count the presidential vote - have caused a split in his party and condemnation from critics who accuse him of undermining democracy.
At Monday's rally in Georgia, Trump again declared the November vote "rigged," an assertion some Republicans worried would dissuade his supporters from voting on Tuesday.
His attacks appear to have undermined public confidence in the electoral system. Edison's exit poll found more than seven in 10 were very or somewhat confident their votes would be counted accurately, down from 85% who said the same in a Nov. 3 exit poll.
Wall Street's main indexes finished higher after a weak start on Tuesday as investors awaited the outcome in Georgia.
If elected, Warnock would become Georgia's first Black U.S. senator and Ossoff, at 33, the Senate's youngest member. Perdue is a former Fortune 500 executive who has served one Senate term. Loeffler, one of the wealthiest members of Congress, was appointed a year ago to fill the seat of a retiring senator.